Fantastical works as a front end for iCal, Entourage, and Outlook (along with Google Calendar or Yahoo Calendar if you add them to iCal), and that's exactly how you'd use it, transitioning those big calendar apps to the role of back-end database for your fancy Fantastical interface. Invoke Fantastical with a global keyboard shortcut, start typing event details ("Dinner with Ellen tomorrow at 6pm"), and it translates the event as you type, even recognizing participants and to connect them with your Address Book contacts. At a whopping $20 for a license, Fantastical isn't cheap, especially considering that it is still just a menu-bar front end for other calendaring tools. That said, if you're looking for a better way to access and add events to your desktop calendar, it doesn't get much better than Fantastical.